Find or purchase a piece of high-carbon steel. While any piece of steel is usable, harder steel will cause smaller pieces to break off when it is struck by the flint, which increases the chances for a spark to occur. A good piece of steel should be easy to hold, with an edged or curved area that can be struck to create sparks.
Obtain a piece of flint or other strong, dense rock that can be fractured to create a sharp edge. Flint is a common, sedimentary rock that can be found in many places, but agate, quartz, jade, bloodstone and many others work just as well.
Fracture the stone so that a sharp edge is created. In the wilderness, this can be done by striking it against another hard piece of rock and then grinding the edge that is created against a flat stone to create a blade. At home, tools like a grinder or steel file are efficient for blade making.
Keep the steel and flint together in a pouch so that they don't become separated. Continued use of the flint will cause it to become dull, so occasionally sharpen it to obtain the best use from it.
